Abstract: Objective To explore the efficacy and safety of telbivudine （LDT） in blocking mother-to-child hepatitis B virus（HBV） transmission before or after pregnancy in human. Method 180 serum HBsAg-positive young women whose husbands were HBsAg-negative were recruited in this study. The women in group A （n=60） received oral administration of telbivudine before and throughout their pregnancy, and the pregnancy began not until their serum HBV DNA turned negative;the women in group B（n=60） received oral administration of telbivudine from 24-week gestation to the delivery,and the in control group （n=60） received no anti-viral treatment. The positive rates of serum HBsAg and HBV DNA in children after birth, at 24 w and at 48 w were recorded. Results The positive rates of serum HBsAg and HBV DNA in intervention group A were both 0.0% at birth,aged at 24-week or 48-week;the positive rates of serum HBV DNA in group B were 5.0%,3.3% and 3.3% at birth,24-week and 48-week ages,respectively,and there was a significant difference between group A and group B（P<0.01）;the positive rates of serum HBV DNA in control group were 20.0%,18.3% and 16.7%, respectively,at birth,24-week and 48-week age,and there was a significant difference between group B and group control （P<0.05）;no women reported telbivudine discontinuation due to adverse reaction;the gestational age, weight,body length and Apgar’s score of newborn babies in three groups had no statistical difference. Conclusion Oral administration of telbivudine before pregnancy can result in complete interruption of intrauterine mother-to-child HBV transmission with favorable safety for both pregnant women and newborns.

Key words: Hepatitis B, Telbivudine, Intrauterine transmission, Mother-to-infant transmission, Safety